Add opt-in autostart desktop entry for the tray applet

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

packaging/enodia-sentinel-tray.desktop

@@ -0,0 +1,9 @@
+[Desktop Entry]
+Type=Application
+Name=Enodia Sentinel Tray
+Comment=Tray launcher for the Enodia Sentinel security agent
+Exec=enodia-sentinel-tray
+Icon=security-high
+Terminal=false
+Categories=System;Security;Utility;
+X-GNOME-Autostart-enabled=true

tests/test_packaging.py

@@ -157,5 +157,14 @@ class TestSourceInstallPackaging(unittest.TestCase):
             self.assertIn(phrase, guide)
 
 
+class TestTrayDesktopEntry(unittest.TestCase):
+    def test_desktop_file_launches_tray_entry_point(self):
+        text = _read("packaging/enodia-sentinel-tray.desktop")
+        self.assertIn("[Desktop Entry]", text)
+        self.assertIn("Type=Application", text)
+        self.assertIn("Exec=enodia-sentinel-tray", text)
+        self.assertRegex(text, r"(?m)^Name=.*Sentinel")
+
+
 if __name__ == "__main__":
     unittest.main()